JPS62245329A - Position detecting device - Google Patents

Abstract

PURPOSE:To simplify the constitution of a position detecting part by detecting a position through the use of a resistance value varying corresponding to a magnetic bias quantity applied on a magnetic substance. CONSTITUTION:A position detecting device is constituted of a position detecting part 10 consisting of lengthy shape magnetic substance 11a-11h arranged in parallel keeping a prescribed space with each other, an input pen 20 which generates a magnetic bias, a conversion circuit 30, a signal selection circuit 40 which switches and connects the conversion circuit 30, and the above stated magnetic substance 11a-11h, and a position detection circuit 50. And by positioning one end of the input pen 20 on the upper parts of the magnetic substance 11a-11h, and applying the magnetic bias from the tip of the pen, the resistance value R of each of the magnetic substance 11a-11h shows the minimum value for the magnetic substance 11 positioned nearest to the position, and the values go higher gradually as they are separated from the position. In this way, respective voltage of each of the magnetic substance 11a-11h in an X direction is taken out at the position detection circuit 50, from the state of the resistance value R, and a voltage value having the minimum value is found by performing an arithmetic operation, thereby the coordinate value of the input pen 20 being decided.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention provides a method for detecting a specified position based on a change in the impedance, particularly the resistance value, of a magnetic material that has been subjected to magnetic generation and evaporation. This invention relates to a detection device.

(Prior art) As a conventional position detection device, a pulse current is applied to a drive coil provided at one end of a magnetostrictive transmission medium or at the tip of a position indicating ben, and magnetostrictive vibration waves are generated in the magnetostrictive transmission medium. The time required to detect the induced magnetic pressure based on the magnetostrictive vibration waves in the detection coil provided at the tip of the positioning pen or one end of the magnetostrictive transmission medium is measured by a processor, etc., and from this time the indicated position of the positioning pen is determined. There was something that was done to calculate the . In addition, as another conventional position detection device, a plurality of drive lines and detection lines are arranged perpendicularly to each other, and current is sequentially applied to the drive lines and detection lines are sequentially selected to detect induced voltage. There is a device in which a position specified by a position indicating pen made of a magnetic material such as ferrite is detected from the position of a detection line where a large induced voltage is induced.

(Problems to be Solved by the Invention) Although the former device a has relatively good position detection accuracy,
In order to send and receive timing signals, etc. between the pen and the processor, etc., a cord is required between the pen and the device, and its handling is severely restricted, and it is also susceptible to guidance from other devices, causing malfunctions and In addition, there is a possibility that the pen may become a source of noise, and furthermore, there are other problems such as the need to hold the pen perpendicular to the magnetostrictive transmission medium and to point it fairly close to it. In addition, in the latter device, the positioning pen can be cordless, but the resolution of the coordinate position is determined by the spacing between the lines, and if the spacing between the lines is made small to increase the resolution, the S/N ratio and stability will deteriorate. It is difficult to increase the resolution, it is difficult to detect the position of the true ridge at the intersection of the drive line and the detection line, and the positioning pen must be placed very close to the line, making it difficult to use thick objects on the input surface. There were problems such as not being able to use it with the

The present invention improves these conventional drawbacks, and
To provide a highly accurate position detecting device which has good operability since a magnetic generator for specifying a position is not connected anywhere, is strong against external guidance, and does not emit noise.

(Means for Solving the Problems) The position detection device of the present invention has a plurality of long magnetic bodies 118 to 11[1] arranged substantially parallel to each other at predetermined intervals as shown in FIG. a position detection unit 10 equipped with a position detection unit 10, a position designating magnetic generator that generates a steady magnetic field, such as an input pen 20, a conversion circuit 30 that converts the impedance value of a conductor into an electrical signal, and the conversion circuit 30 and the Position detection section 10
a signal selection circuit 40 that connects the plurality of magnetic bodies 11a to 11h by cutting and connecting the plurality of magnetic bodies 11a to 11h;
It is comprised of a position detection circuit 50 that calculates the indicated position of the input ben 20 from electrical signals corresponding to each of 18 to 11h.

(Function) The impedance value, especially the resistance value R, of the magnetic bodies 11a to 11h can be expressed as R-(J/S)ρ (where l is the length of the magnetic body, and S &, is the magnetic body , and ρ is the resistivity.) here,! , S are determined by the specific dimensions of the magnetic bodies 11a to 11h used and can be assumed not to change, so the resistance value R is proportional to the specific resistance ρ of the magnetic bodies 118 to 11h.

By the way, the specific resistance ρ of the magnetic bodies 11a to 11h changes greatly depending on the magnetic bias applied from the outside. The nature of this change varies depending on the composition of the magnetic material, the frequency of the alternating current, or whether the magnetic material is subjected to heat treatment or magnetic field treatment, but generally it has a negative characteristic, that is, the more magnetic bias is applied, the smaller it becomes. shows. Therefore, as shown in FIG. 2, one end of the human-powered pen 20 containing the bar magnet 21 is positioned above the magnetic bodies 11a to 11h, and a constant magnetic field (hereinafter referred to as magnetic bias) is applied to the tip. In addition, the resistance value R of each of the magnetic bodies 118 to 11h takes the resistance value of the magnetic body closest to the position where the input ben 20 is placed as the minimum value, and gradually increases as it moves away from this value.

Here, it is possible to directly obtain the resistance value R, but since the subsequent processing is difficult, the resistance value R of each of the magnetic bodies 118 to 11h is determined by an electric signal, e.g., by the conversion circuit 30 and the signal selection circuit 40. Convert to voltage. Figure 3 shows each magnetic body 1
The voltage values ■1 to v8 corresponding to the resistance values R of 18 to 11h are shown, and the horizontal axis indicates the coordinate position in the direction perpendicular to the magnetic bodies 11a to 11h (hereinafter referred to as the X direction).
The vertical axis shows voltage. Note that the coordinate values x1 to x8 indicate the positions of the respective magnetic bodies 11a to 11h in the X direction. The X coordinate value XS of the input pen 20 can be determined by extracting each of the voltages v1 to v8 with the position detection circuit 50 and calculating the X coordinate value at which the voltage value becomes the minimum value by performing mathematical processing.

Further, even if the input pen 20 is moved along the magnetic bodies 11a to 11h, the magnetic bias group applied to each magnetic body does not change, so the same X coordinate value can be obtained. Furthermore, by combining two position detection units 10 orthogonal to each other, so-called two-dimensional coordinate values in the X and Y directions can also be obtained.

One of the calculation methods for determining the coordinates 1+TJ x is as follows:
There is a method of approximating the waveform near the minimum value (here, the same as the minimum value) in FIG. 3 by an appropriate function and finding the coordinates of the minimum value of the function. For example, each magnetic body 11a to 11h
Let the interval of
By approximating up to 5 using a quadratic function (indicated by a solid line in the figure), it can be calculated as follows. First, from each voltage value and coordinate value, V3=a(x3-x,)2+b...-(1)V4=
a (x4-x,) +b -----(2)V5
=a (x5−x,) +b −・−・・−(3
). Here, a and b are constants (a>O).

Also, x4−×3=ΔX (4
)x s x 3=2Δχ system...(5
). Substituting equations (4) and (5) into equations (2) and (3) and rearranging, x, +=x3+ , jx/2 ((3V3-4V4+v
5)/(v3-2V4+v5)) ......(6) It becomes. Therefore, the voltages v, V4 .corresponding to the resistance values R of the magnetic bodies 11c, 11d, lie. v5, and coordinate value ×
3 (known), the X coordinate value X of the input pen 20 can be calculated by calculating the equation (6) in the position detection circuit 5o.

Detection can be made in the same manner in the case of a magnetic material whose resistance value increases as the magnetic bias increases.

(Example) FIG. 4 is a perspective view showing a specific configuration of the position detection section 10. The magnetic bodies 11a to 11h are difficult to magnetize even when a magnet is brought close to them, that is, have a small holding force, and are transparent 11
The wire is made of a material with a high coefficient of oxidation, such as an amorphous wire with a circular cross-section and a diameter of about 0.1 u. As an amorphous wire, for example, (Fe1-xCOx)7.5i1oB15(
(atomic %) (X does not indicate the ratio with 1"el!:co, and takes a value of O to 1). Also, 12
is a substrate on which the magnetic bodies 11a to 11h are fixed,
A printed circuit board with a copper plate attached to one side of an insulating substrate made of glass epoxy or the like is etched, and at one end there are conductors having the same number as the magnetic bodies 118 to 11h, that is, eight land portions 13a to 13h. 13, and eight land-shaped conductors 14a to 1411 are similarly formed at the other end.

Both ends of the magnetic bodies 118 to 11h are connected to the conductor 13.
are soldered to the land portions 13a to 13h and conductors 14a to 14h, respectively, and the portions between them are fixed to the substrate 12 with an adhesive or the like, and are spaced apart from each other at a predetermined interval (approximately 511 mm).
1) They are arranged parallel to each other. Note that the conductor 13
are connected from one end thereof to a conversion circuit 30 via a lead wire 15, and each of the conductors 14a to 14h is connected to a signal selection circuit 40 via lead wires 16a to 16h, respectively.

Note that as the magnetic material, a material whose surface is coated with vinyl chloride or the like may be used, and in this case, it can also be fixed to the substrate by thermocompression bonding or the like.

FIG. 5 is a sectional view showing a specific example of the input vent 20, and FIG. 6 is an electric circuit diagram thereof. In the figure, reference numeral 22 denotes a pen-shaped 8-pin made of synthetic resin or the like, and a bar magnet 21 with a tapered tip is housed in one end of the pen-shaped rod so as to be movable in the axial direction.

In addition, an infrared transmitting window 23 made of transparent plastic or the like is provided along the circumferential direction on the other end side of the container 22, and inside the window 23 is a reflector 24 having a conical circumferential surface coated with chrome plating or the like. An infrared light emitting diode 25 is housed therein. 26a and 26b are operation switches, and the operation switch 26
a is attached to one side of the tip side of the container 22, and an operation switch 26b is attached opposite to the other end of the bar magnet 21. Further, 27 is a signal generation circuit, 28 is a battery, and the container 2
It is stored in the appropriate place within 2.

The signal generation circuit 27 converts a plurality of (in this case three) commands to the position detection circuit 50, such as measurement start and position input, into a plurality of code signals based on a combination of several pulse signals, and a decoder 27a. , a code signal generator 27b, and a diode driving transistor 27c, and generates a code signal to drive the light emitting diode 25 according to the on/off combination of the operation switches 26a and 26b. When the operation switch 26a is turned on, an infrared signal indicating a measurement start code is sent to the diode 25.
When the tip of the bar magnet 21 with the cover 29 attached is pressed against the input surface, the bar magnet 21 slides and the switch 2
6b is turned on, and an infrared signal indicating a position input code signal is transmitted.

FIG. 7 shows a specific example of the conversion circuit 30, in which 3
1 is an integrator, 32 is a band pass filter, and 33 is an arithmetic circuit. The integrator 31 receives, at its input terminal 34, a clock pulse (
or a pulse obtained by dividing this), integrate this,
Convert to triangular wave signal. The bandpass filter 32 converts the triangular wave signal into a sine wave signal, and the arithmetic circuit 3 converts the triangular wave signal into a sine wave signal.
Send to 3. The arithmetic circuit 33 consists of an operational amplifier 33a and a resistor 33b.The sine wave signal is input to the inverting input terminal of the operational amplifier 33a via the resistor 33b, and the inverting input terminal and the output terminal are connected to each other. One of the magnetic bodies 11a to 11h is connected therebetween via a signal selection circuit, for example, a well-known multiplexer 40, and the non-inverting input terminal is grounded.

Here, the resistance value of the magnetic bodies 118 to llh is set to R1 resistor 33.
The resistance value of b is R1, and the input voltage of the arithmetic circuit 33 is vl.
, taking the output voltage as v2, v2 =-(R/R1)
・vl becomes. Therefore, if R1 and (1) are constant, the output voltage (2) depends on the resistor IInR, and when the resistance value R decreases, the output voltage (2) also decreases. That is, a decrease in the resistance value R can be detected as a decrease in the output voltage v2. Note that the reason why a clock pulse is used as the reference (input) signal is to synchronize with the position detection circuit 50.

FIG. 8 is a circuit block diagram showing a specific configuration of the position detection circuit 50. In the same figure, there is J3, and the input Ben 20 mentioned above
When an infrared signal is emitted from the light-emitting diode 25 without indicating the code indicating the start of measurement, the infrared signal is received by the infrared receiving diode 51, further amplified and waveform-shaped by the receiver 52, and converted to the original code. It is converted into a signal, further converted back into a measurement start command signal, and sent to the input buffer 53.

The arithmetic processing circuit 54 reads the t'iif command signal into the input buffer 53, and when it recognizes the start of measurement, outputs the output buffer? A control signal is sent to the multiplexer 40 via the multiplexer 55, and the connection between the conversion circuit 30 and the magnetic bodies 118 to llh is switched one after another. The voltage corresponding to the resistance value of each of the magnetic bodies 11a to 11h converted by the conversion circuit 30 is supplied to the amplifier 56.
is input to the detector 57, amplified, rectified by a detector 57, converted into a DC voltage, and then converted into an analog-digital (A/D) voltage.
) is converted into a digital value by the converter 58 and sent to the arithmetic processing circuit 54 via the input buffer 53. The arithmetic processing circuit 54 reads the digital values in synchronization with the control signal and temporarily stores them in the memory 59. Further, the arithmetic processing circuit 54 detects a voltage value near the minimum value from among these, and further dedicates the X coordinate value according to Equation (6).

Figure 9 shows the process flow for detecting voltage values near the minimum value.
Figure 10 shows the flow of calculation processing, and in the figure, S
N is a step number, C8 is a number that does not indicate the number of the magnetic body whose resistance value is to be measured, and SD is sampling data that indicates a gauge value corresponding to the resistance value of the magnetic body.
HL indicates a predetermined judgment level, CN indicates the voltage closest to the detected minimum value, and J indicates the number of the magnetic material, Ml.

M2 is data temporarily stored in memory, [)1, [)
2.

C3, C4, and DS each have a number (CN-2).

(CN-1), (CN), (CN+1>, (CN+2)
This is data sampled when measuring the resistance value of a magnetic material.

The X coordinate value of the digital value obtained in this way is
The value is once stored in the memory 59, but while the signal indicating the start of measurement is being issued, the above-mentioned measurement and calculation are repeated at predetermined intervals, and the value is updated. Next, an infrared signal indicating a position designation code is transmitted from the input pen 20, and when recognized by the arithmetic processing circuit 54 via the light receiving diode 51, receiver 52, and input buffer 53, the digital value at that point is The X coordinate value is sent as an input value via output buffer 760 to a digital display (not shown) for display, or to a computer (not shown) for processing, or to be sent to a digital display (not shown) for processing.
It is converted into an analog signal via an analog (D/Δ) converter 61 and processed.

Note that the number of magnetic bodies in the examples is just an example, and it goes without saying that the number is not limited to this. Furthermore, it has been confirmed through experiments that position detection can be performed with relatively high accuracy if the spacing between the magnetic bodies is approximately 2 to 61a11. Further, the magnetic generator used in the input pen is not limited to a permanent magnet, but may also be an electromagnet.

Furthermore, in the embodiment described above, signals indicating measurement start, position designation, etc. are transmitted from the input pen 20 to the position detection circuit 50 using infrared signals, but ultrasonic signals may also be used. Furthermore, since the signals indicating the start of measurement, position designation, etc. are simply for making the arithmetic processing circuit 54 recognize the timing, they do not particularly need to be sent from the input pen 20, but are sent from the position detection circuit 50 itself. A ghee board installed in the
The signal may be sent from another switch circuit.

FIG. 11 shows another embodiment of the invention. In the figure, reference numerals 71 and 72 indicate position detection units in the X and Y directions, and 73 and 74 indicate signal selection circuits for the X and Y directions, respectively. It has the same configuration as the signal selection circuit 40 (however, the details are omitted in the drawing for simplicity), and the position detection section 71.7
2, the respective magnetic bodies are superimposed on each other so as to be orthogonal to the X direction and the Y direction, respectively.

Further, 75 is a position detection circuit which is similar to the position detection circuit 50 except that position detection in the X direction and the Y direction is performed alternately. Therefore, according to this embodiment, position (coordinate) detection in two directions, the X direction and the Y direction, can be easily performed. Note that the configurations of the input pen and the conversion circuit may be the same as in the previous embodiment.

Further, the position detecting sections 71 and 72 can also be constructed in one piece by providing a magnetic material and its wiring on the front and back surfaces of a single insulating substrate.

(Effects of the Invention) As explained above, according to the present invention, in order to detect the position from the resistance value that changes depending on the amount of magnetic bias applied to the magnetic body, it is only necessary to arrange a plurality of magnetic bodies almost in parallel.
The configuration of the position detection section can be extremely simplified. In addition, since there is no need to exchange signals between the position specifying magnetic generator and other devices for position detection, it can be cordless, and furthermore, the magnetic bias required for position specification can be reduced. Since the amount is only about a few oersteds (Oe), the position can be specified even if the position specifying magnetic generator is separated from the position detecting section by some distance, and the position can also be specified from the back side of the position detecting section. Metals other than ferromagnetic materials can also be placed on the input surface. In addition, since there is no change in magnetic flux during detection, less induced noise is generated to the outside.

Further, if the position detecting sections are provided in the X direction and the Y direction, there are advantages such as two-dimensional position detection becomes possible.

[Brief explanation of drawings]

The drawings serve to explain the present invention.C1: Figure 1 is an explanatory diagram showing the main structure of the present invention; Figure 2 is a diagram showing the state of magnetic flux applied to the magnetic material from the magnetic generator for the index finger window. , 3rd
The figure is a graph showing an example of the voltage value corresponding to the resistance value of the magnetic material, and FIG. 4 is a perspective view of the specific configuration of the position detection unit 10.
Figure 5 is a sectional view showing the specific configuration of the magnetic generator for position designation, Figure 6 is its electrical circuit diagram, Figure 7 is a specific circuit diagram of the conversion circuit, and Figure 8 is the position detection circuit. Figure 9 is a circuit block diagram showing the specific configuration of , Figure 1 is a diagram showing the flow of processing for detecting voltage values near the minimum value, Figure 10 is a diagram showing the flow of calculation processing, and Figure 11 is a diagram showing the flow of processing for detecting voltage values near the minimum value. FIG. 7 is an explanatory diagram showing another embodiment of the invention. DESCRIPTION OF SYMBOLS 10... Position detection part, 20... Magnetic generator for position specification, 30... Conversion circuit, 40... Signal selection circuit, 5
0...Position detection circuit, 11a-11h...Magnetic material,
71...X-direction position detection section, 72...Y-direction position detection section. Patent Applicant Wacom Co., Ltd. Patent Attorney Furu 1) Takashi Lie X) Heading to Sonono 1 Figure 8

Claims (2)

[Claims] (1) A position detection unit equipped with a plurality of long magnetic bodies arranged substantially parallel to each other at predetermined intervals; a position designating magnetic generator that generates a steady magnetic field; a conversion circuit that converts the signal into a signal; a signal selection circuit that switches and connects the conversion circuit and the plurality of magnetic bodies of the position detection section; A position detection device comprising a position detection circuit that calculates the indicated position of a designated magnetic generator. (2) an X-direction position detection unit including a plurality of elongated X-direction magnetic bodies arranged substantially parallel to each other at predetermined intervals; A superimposed Y direction position detection section, a position specifying magnetic generator that generates a steady magnetic field, a conversion circuit that converts the impedance value of the conductor into an electrical signal, and the conversion circuit and the X and Y direction positions. an X-direction and Y-direction signal selection circuit that switches and connects the plurality of magnetic bodies of the detection section; and a signal selection circuit for selecting the position specifying magnet from an electric signal corresponding to each of the plurality of magnetic bodies of the X-direction and Y-direction position detection section. A position detection device comprising a position detection circuit that calculates the indicated position of the generator in the X and Y directions.